Self‐Supported Ru‐CoFe Prussian Blue Analogues for Selective and Scalable Electrooxidation of 5‐Hydroxymethylfurfural to 2,5‐Furandicarboxylic Acid

Abstract The electrochemical upgrading of biomass‐derived 5‐hydroxymethylfurfural (HMF) into 2,5‐furandicarboxylic acid (FDCA) represents a promising route for producing renewable monomers for biodegradable plastics. However, achieving high conversion and selectivity under industrially relevant conditions remains challenging due to sluggish kinetics and catalyst instability. Herein, we report the rational design of a Ru‐doped CoFe Prussian blue analogue (Ru‐CoFe PBA) catalyst directly grown on copper foam via a one‐step hydrothermal process. Comprehensive structural and electronic characterizations reveal that Ru incorporation induces an electron‐deficient state in Co and Fe centers, thereby facilitating the formation of hydroxide species and enhancing HMF adsorption. As a result, the Ru‐CoFe PBA/CF electrode exhibits outstanding electrocatalytic activity for HMF oxidation, achieving 100% conversion, 98.9% FDCA selectivity, and 97% Faradaic efficiency in 1 M KOH with 100 mM HMF, along with excellent cycling stability. Furthermore, deployment in a multi‐stage continuous flow reactor enables high HMF conversion and FDCA selectivity under a broad range of operational parameters, maintaining stable performance over 150 h of continuous operation. This work highlights the synergistic benefits of heteroatom engineering and flow reactor design, offering a scalable platform for efficient biomass electrooxidation to value‐added chemicals.